R help - Jul 2012 - Creating Multiple Repeating samples and Cross Correlating them.

I'm having a lot of trouble getting this done and nothing I've written
has
been remotely successful. Basically I have about 64 binary data sets stored
as vectors, with 72900 entries in each. I am not very familiar with cross
correlations, but I was advised that I should create 1000 randomized date
sets (used sample() for that) to use as a control, then compare the cross
correlation of my real data sets to the controls. First of all I am having
trouble creating 1000 different sample()'s of the same vector, and then I am
not all too sure how to cross correlate them Nothing seems to produce what I
want, all I get are copies of the same sample() of the vector repeated over
and over. Please Help?

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It would help if you supplied some code for us to see what you have tried.
However something like this would presumably give you the sample data sets
--note only n=100 in the example.


mymat  <-  matrix(NA, ncol=  100, nrow= 100)
for (n in 1: 100) {
  mymat[,n] <-  sample(c(0,1), 100, replace = TRUE)
}
mymat


John Kane
Kingston ON Canada

> -----Original Message-----
> From: baileycr at ohsu.edu
> Sent: Thu, 19 Jul 2012 14:17:43 -0700 (PDT)
> To: r-help at r-project.org
> Subject: [R] Creating Multiple Repeating samples and Cross Correlating
> them.
> 
> I'm having a lot of trouble getting this done and nothing I've
written
> has
> been remotely successful. Basically I have about 64 binary data sets
> stored
> as vectors, with 72900 entries in each. I am not very familiar with cross
> correlations, but I was advised that I should create 1000 randomized date
> sets (used sample() for that) to use as a control, then compare the cross
> correlation of my real data sets to the controls. First of all I am
> having
> trouble creating 1000 different sample()'s of the same vector, and then
I
> am
> not all too sure how to cross correlate them Nothing seems to produce
> what I
> want, all I get are copies of the same sample() of the vector repeated
> over
> and over. Please Help?
> 
> --
> View this message in context:
>
http://r.789695.n4.nabble.com/Creating-Multiple-Repeating-samples-and-Cross-Correlating-them-tp4637131.html
> Sent from the R help mailing list archive at Nabble.com.
> 
> ______________________________________________
> R-help at r-project.org mailing list
> https://stat.ethz.ch/mailman/listinfo/r-help
> PLEASE do read the posting guide
> http://www.R-project.org/posting-guide.html
> and provide commented, minimal, self-contained, reproducible code.
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